Mathematica 9 is now available
Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2010

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: How to construct symmetric matrix from just a one

  • To: mathgroup at smc.vnet.net
  • Subject: [mg110419] Re: How to construct symmetric matrix from just a one
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Thu, 17 Jun 2010 02:04:21 -0400 (EDT)

SetAttributes[f, HoldAll];

f[mat_?MatrixQ] :=
 Module[
  {n = Length[mat]},
  Table[
   mat[[r, c]] = mat[[c, r]],
   {r, n - 1}, {c, r + 1, n}];
  m]

m = {{1, 0, 0, 0},
   {2, 3, 0, 0},
   {4, 9, 5, 0},
   {2, 2, 3, 4}};

f[m]

{{1, 2, 4, 2}, {2, 3, 9, 2}, {4, 9, 5, 3}, {2, 2, 3, 4}}


Bob Hanlon

---- dragec <culinovic at gmail.com> wrote: 

=============
please help me with simple to apply function that will construct
symmetric matrix from given just a half matrix with diagonal.
Eg:

From:
1  0  0  0
2  3  0  0
4  9  5  0
2  2  3  4

To give:

1  2  4  2
2  3  9  2
4  9  5  3
2  2  3  4



  • Prev by Date: Ballistic launch trajectory code
  • Next by Date: Re: Simplification question
  • Previous by thread: Re: How to construct symmetric matrix from just a one
  • Next by thread: Normal with GeometricTransformation